1 | .TH "roar_vs_volume_get" "3" "May 2011" "RoarAudio" "RoarAudio Programmer's Manual" |
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2 | |
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3 | .SH NAME |
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4 | roar_vs_volume_get, roar_vs_volume_mono, roar_vs_volume_stereo \- Get or set volume for audio stream |
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5 | |
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6 | .SH SYNOPSIS |
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7 | |
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8 | #include <roaraudio.h> |
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9 | |
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10 | int roar_vs_volume_get (roar_vs_t * vss, float * l, float * r, int * error); |
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11 | |
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12 | int roar_vs_volume_mono (roar_vs_t * vss, float c, int * error); |
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13 | |
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14 | int roar_vs_volume_stereo (roar_vs_t * vss, float l, float r, int * error); |
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15 | |
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16 | .SH "DESCRIPTION" |
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17 | Those functions are used to get or set volume for the given stream. |
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18 | |
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19 | \fBroar_vs_volume_get()\fR gets the volume for the given stream in stereo form as |
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20 | a left and a right component (L/R). If you need the mono volume just devide the sum of both |
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21 | by two. See examples below. |
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22 | |
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23 | \fBroar_vs_volume_mono()\fR sets the mono volume for the stream. Balance information is not kept. |
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24 | |
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25 | \fBroar_vs_volume_stereo()\fR sets the stereo volume for the stream as left and rigth component (L/R). |
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26 | |
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27 | .SH "PARAMETERS" |
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28 | .TP |
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29 | \fBvss\fR |
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30 | The VS object for wich volume is get or set. |
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31 | |
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32 | .TP |
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33 | \fBl\fR, \fBr\fR, \fBc\fR |
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34 | The volume for left, right or center (mono) channel. Value is a float in range zero to one. |
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35 | Zero means this channel is fully muted. One means the channel is passed without altering the amplitude. |
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36 | |
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37 | Small numerical errors are detected and corrected. Bigger errors will result in a out of range error. |
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38 | |
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39 | Note that to mute the stream you MUST NOT use volume setting but \fBroar_vs_mute\fR(3). |
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40 | |
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41 | .TP |
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42 | \fBerror\fR |
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43 | This is a pointer to a integer used to store the error value in case of error. |
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44 | This can be NULL if not used but it is very recommended to use this error value to report |
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45 | good error messages to the user. |
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46 | |
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47 | .SH "RETURN VALUE" |
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48 | On success these calls return 0. On error, \-1 is returned. |
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49 | |
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50 | .SH "EXAMPLES" |
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51 | Getting mono volume: |
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52 | |
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53 | float l, r, c; |
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54 | int err; |
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55 | |
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56 | if ( roar_vs_volume_get(vss, &l, &r, &err) == \-1 ) { |
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57 | /* handle error */ |
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58 | } |
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59 | c = (l + r)/2.; |
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60 | |
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61 | .SH "SEE ALSO" |
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62 | \fBroarvs\fR(7), |
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63 | \fBlibroar\fR(7), |
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64 | \fBRoarAudio\fR(7). |
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65 | |
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66 | .\" ll |
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